1. Field of the Invention
The present invention relates to a system for creating and modifying a boundary shape of the required/presented solid in the field of CAD (Computer Aided Design) and/or CAM (Computer Aided Manufacturing), NC machine tool, computer graphics, computer vision and the like.
2. Description of the Prior Art
In CAD/CAM, computer vision or the like, conventionally there are well known three types of modellings to express a desired or predetermined form. Those are a wire frame modeller, a surface modeller, and a solid modeller.
Briefly, as for the wire frame modeller, the above kinds of forms can be expressed by using constructed points which are roughly populated as a finite type of a set which has lower density.
As for the surface modeller, these forms can be also expressed by the same type of a set which has higher density.
In these cases, the two modellers of the above type can be performed by the way estimating the lacked points among the given points obtained so as to express the form, that is by means of interpolation operation based on the functional approximation. The solid modeller piles up simple or primitive forms obtained as the typical sets in which the points are densely populated in a manner similar to a building-blocks work to express a predetermined form. Each of these three conventional methods features a function to express forms for solid bodies.
However, when used to express a three-dimensional form, the above-mentioned prior art method lack is flexibility of expression; therefore, they are unable to perform their functions sufficiently. Also, it is well known that a form expression is one embodiment of a form producing/finishing process while a form creation is also another one embodiment of the same process. All of the conventional modellings, however, are incapable of performing a continuous and throughout processing operation between these two embodiments.
For example, even when the prior art of solid modeller is used, some of three-dimensional forms can be indeed expressed by means of combination of simple forms, but the solid model method inherently can not provide a free and detailed expression of such three-dimensional form. Thus, it can be naturally said that it is almost impossible to carry out a continuous and throughout processing operation from the form expression step to the form creation step.